1. Field of the Invention
This invention relates generally to a biological signal processing system for essentially real-time analyzing and displaying biological signals, such as brain waves.
2. Description of the Prior Art
A concept, called biofeedback, is publicly known as an attempt to voluntarily control those functions of a human body which are usually controlled autonomically (involuntarily) or reflexly. That is, successful attempts have been made to inform a subject of the analysis results of brain waves indicating that he (or she) is in a high .alpha.-wave intensity and to acquaint him (or her) with his (or her) own conditions at that .alpha.-wave intensity so that he (or she) can make efforts to maintain his bodily and mental conditions at a level that can readily induce that state of brain waves has already been put into practical usefulness.
Needless to say, additional benefits associated with the biofeedback technology include;
(1) Fundamental knowledge as to the information necessary to use biological information
(2) Clues for changing biological activities by psychological means, and proper orientation to achieve the purpose
(3) Encouragement and assistance of help to reinforce learning experience
(4) Confirmation by a subject of the information experienced by integrating the information derived from his (or her) own memory and newly perceived from biofeedback signals with the internally perceived information through bodily and mental experience.
This concept has been gradually developed as the argument that the learning technique used for the therapy of the central (voluntary) nervous system can also be applied to the autonomic (involuntary) nervous system was brought forth in the 1960s, and N. E. Miller demonstrated in 1969 that animals can control those functions which had previously been regarded as involuntary.
However, the components of brain-wave signals have heretofore been processed with the fast Fourier transformation (FFT) technique in analyzing brain waves, for example, in real time, as discussed in Steve Ciarcia, "Computers on the Brain" pp. 289-296, "BYTE," July 1988.
FIG. 14 shows the conventional construction of FFT processing. In the figure, reference numeral 1-1 refers to Channel 1 signal; 1-2 to Channel 2 signal; 2 to an FFT processing section; 3 to a square-root reference table; 4 to a sine/cosine reference table; 5-1 to a left-brain power component array; 5-2 to a left-brain phase array; 6-1 to a right-brain power component array; and 6-2 to right-brain phase array, respectively.
The FFT processing section receives the left-brain sample train and the right-brain sample train to perform fast Fourier transformation while referring to the tables 3 and 4 to produce the component arrays 5 and 6 shown in the figure for visual representation, though not shown in the figure.
As shown in FIG. 14, the prior art employs fast Fourier transformation processing. to perform real-time processing, therefore, a relatively large computer has to be used.